Says deviation of 7 days before or after due date is expected

The northeast monsoon is likely to set in around October 26 and the State may witness rains in one or two places till Thursday, the Meteorological Department said on Monday.

Though the northeast monsoon usually starts around October 20, a deviation of seven days before or after this date is considered normal. The NE monsoon is important as it accounts for 48% of the annual rainfall that the State receives. Coastal districts depend on the NE monsoon for 60% of their yearly rainfall. Met department officials said a cyclonic circulation over Sri Lanka and the neighbourhood that extends up to 3.1 km above the mean sea level would bring in isolated heavy rainfall over the State till Thursday.

There may be an increase in rainfall activity, particularly over coastal parts of Tamil Nadu and Puducherry from Friday.

Places like Chennai may experience light rain or thundershowers in some areas till Wednesday. The maximum temperature in the city will remain close to the normal of 33 degree Celsius.

Normalcy to persist

Sunday’s low pressure area over the North Andaman sea and adjoining Myanmar is now lying over the Gulf of Martaban and the neighbourhood. This may intensify into a well-marked low pressure area by Tuesday. However, this mignt not influence rain over Tamil Nadu, said officials. Though the monsoon is yet to begin, the State has already received 15 cm of rain, 18% more than the average for the period starting October 1.